Piano construction



Au8 29, 1933- F. w. KRINGl-:L

PIANO CONSTRUCTION Filed March 2l, 1932 Patented Aug. 29, 1933 UNITED c STATES PATENT OFFICE Claims.

This invention relates to a musical instrument and particularly pertains to piano construction. In the construction of the frame of a piano upon which the strings are strung, it is common 5 practice tol secure the dead ends of the strings to nxed posts and to secure the opposite ends of the strings to adjustable tuning pins. These tuning pins are usually mounted in the wrest plank of the piano frame, and project a considerable distance from the face of the frame. The strings are held under tension by the pins and by added tension imposed by the pressure bar. Due to this construction and tension the portion of the pins projecting from the wrest plank are subjected to considerable strain so that the levermay cause the pins to yield in their seats or to lex with the result that the tuning of the keys will not be permanent.

It is the principal object of the present invention to provide a wrest plank construction which insure that the pins will be held rigid at all times without ilexure and in a manner to make it possible to readily manipulate them in tuning thepiano.

The-present invention contemplates the provision'of a tuning pin adapted to be rotatably supported in the wrest plank of a piano at one end, and rotatably supported by a plate adjacent its opposite end whereby the string may be fastened to the pin intermediate these supports, and may be subjected to considerable tension without imposing objectionable strain upon the pins.

The invention is illustrated by way of example in the accompanying drawing, inwhich:

Figure 1 is a View in transverse section through the wrest plank of a piano frame and a fragmentaryportion of the sound board, showing the application of the present invention thereto.

Fig. 2 is a view in transverse section through the wrest plank as seen on the line 2-2 of Fig. l.

Fig. 3 is a fragmentary view in plan showing the manner in which the tuning pins are mounted upon the wrest plank plate.

Fig. 4 is a View in perspective showing one of the tuning keys and the bearing collar carried thereby.

Referring more particularly to the drawing, indicates the sound board of a piano. At one end of the sound board is a plate 11 carrying pins 12 upon which the dead ends of strings 13 are secured. The strings 13 extend substantially parallel to the sound board and pass over a bridge 14. The strings 13 then extend to the wrest plank 15 of a piano frame. This plank is usually made of a plurality of plies of veneer, and

it is here shown as having a metal angle plate 16 disposed thereover. This angle plate has a portion 17 extending over the face of the wrest plank and a portion 18 extending downwardly over one p edge of the wrest plank. At the corner formed by these two portions of the plate 16 a fret 19 is formed. The strings 13 are drawn over this fret and are held in forcible contact therewith by the pressure bar 20 which is a plate unit. rThis bar is disposed upon the opposite sides ci the strings from the fret 19 and is formed with a V-shaped edge 21 which contacts with the strings and exerts considerable pressure upon them. The hammers 22 of the piano action strike the strings at a point between the edge 21 of the pressure bar and the bridge 14. The ends of the strings which extend over the plate are wrapped around the body of tuninfT pins 23. The end of a particular string extends through an opening 24 in its tuning pin. 0

It is usual practice to wrap the string around the tuning pin so that the coil of the string will occur between the opening 24 in the pin and the face of the wrest plank. This causes the end of the string to be objectionably drawn down against Q the wrest plank and over the fret when the piano is repeatedly tuned. In the present instance the string is wrapped around the tuning pin so that a coil will occur upon the outer end `of the pin and beyond the string opening 24 in the pin. It will be understood that the strings are tightened by the rotation of the tuning pins, and that the strings will be held in tension in direct proportion to the amount of rigidity in the tuning pins and the lack of flexure or rotation of these pins. In the 99 present instance these desirable results are accomplished by forming the wrest plank plate with a plurality of ribs which extend across the face of the plate and along the usual line assumed by the tuning pins. U

By reference to Fig. 3 of the drawing, it will be seen that a rib is indicated at 25 and that it is inclined to the general direction of strings 13. These ribs and the plate are formed with a bore 26 which is of greater diameter than the pin, and in fact, the diameter of the opening 26 through the plate portion 17 is greater than the width of the rib 25. This causes a passageway to be formed through the rib and constituting diametrically opposed faces 27. Mounted between these faces is a tapered brass collar 28 which securely conforms to the arc of the faces and has a central bore to accommodate the outer end of the tuning pin 23. The collar is preferably forced into position between the shoulders of the rib so that it will prolos vide a suitable bearing for the outer end of the pin. The width of the collar is such as to insure that its inner face will lie in a plane spaced from the outer face of the plate portion 17. In that manner the coiled end of the string will be accommodated between the plate and the collar, thus causing the string to be heid and supported upon the tuning pin in substantially the same manner as that embodied in violin construction. This will preclude the possibility of any undue leverage or tension of an over-hanging tuning pin, and will insure that the piano may be readily tuned, and that it will remain in its tuned condition, even though the piano is used by vigorous pianists in interpreting extreme forte movements.

In operation of the present invention the wrest plank is constructed and assembled as shown in Fig. 1 of the drawing, and the strings are drawn taut and tuned after having been fastened to the posts 12 at their dead ends and wrapped around the tuning pins 23 at their adjustable ends. The strings may then be manipulated to be tuned and will be at all times held between two rotatable bearing supports which will prevent the pins from canting in their mounting or flexing beyond the face of the wrest plank, while at the same time insuring that ready access may be had to the pins and the strings.

Attention is directed to the fact that the tapered bearing collars 28 do not completely encircle the pins but are opened on one side to provide a space 30. This opening aiords easy access to the string 13 and makes it possible to readily restring a key without the obstruction of the enlarged collar.

It will thus be seen that the device here disclosed while simple in its construction, provides desirable means for tuning piano strings and holding them in their tuned positions without danger of a drop in pitch of the string due to mechanical imperfections of the constructions now used.

Attention is also directed to the fact that by the construction here shown the piano string is not disposed at an extreme angle to the pressure bar 20, thus insuring that there will be no undue binding of the string between the tuning pin and the fret 19 or the pressure bar. This will render piano tuning less difficult.

While I have shown the preferred form of my invention, as now known to Ine, it will be understood that various changes may be made in combination, construction, and arrangement of parts by those skilled in the art Without departing from the spirit of my invention as claimed.

Having thus described my invention what I claim and desire to secure by Letters Patent is:-

1. In a piano construction a tuning pin around which a piano string is wrapped, a structure for receiving the tuning pin which structure includes a wrest plank and a mounting plate, said structure being characterized by providing a support for the tuning pin upon opposite sides of its string.

2. In piano construction a sound board, a piano frame including a wrest plank, strings stretched across the sound board, tuning pins rotatably mounted in the wrest plank for receiving one end of each of the strings, a mounting plate upon the wrest plank and having bearing portions rotatably supporting the upper ends of the tuning pins, and an intermediate recess to accommodate the portion of the string which is wound around the tuning pin.

3. In piano construction, means for adjustably holding one end of a piano string which includes a wrest plank, a plate disposed thereover and having an opening therethrough to accommodate a tuning pin which is rotatably supported in the wrest plank, said opening being larger than the outside diameter of the tuning pin, ribs mounted upon the plate and extending upwardly upon opposite sides of the tuning pin and between which a tapered bearing collar is supported, said collar providing a rotatable support for the upper end of the pin.

4. In piano construction, a wrest plank to which the adjustable ends of piano strings are secured, a plate mounted over said wrest plank and formed along one edge with a fret over which the piano strings are drawn, tuning pins extending through the plate and into bores formed in the wrest plank where they are frictionally held, openings being formed through the plate to accommodate the tuning pins, ribs extending upwardly from the outer face of the plate and through which ribs the pins extend, and bearing rings held by the ribs and providing a rotatable support for the tuning pins.

5. In piano construction a piano frame including a wrest plank, a plate upon the face of the wrest plank, tuning pins extending through openings in the wrest plank where they are frictionally held and which pins extend through openings in the plate, said holes being of substantially larger diameter than the pins, a rib formed upon the face of the plate the line of which extends across the center of the tuning pin opening, said rib being narrower than the diameter of the tuning pin opening and being interrupted for a space the width of the tuning pin opening, and a tapered bearing collar interposed between the contiguous faces of the rib and through which collar the tuning pin extends and by which its outer end is rotatably supported.

FRANK W. KRINGEL. 

